I think you should stray away from the Gibson original as much as possible if you want a good bass!!!
Don't make it short scale, the Flying V body needs all the authority it can have, so make it long scale. Don't use an alder body like the original, that sounds kind of lifeless and doesn't project a lot of mids.
Long scale, maple (or maho) neck, maple body and the most assertive pups you can find (TB Plus) to give the instrument a fighting chance to sound well.
I have four Flying V basses, here's a short description of all of them:
- Dean DOA: maho body and neck, long scale, 24 frets, set neck, passive EMG type pups with active circuit, sounds Thunderbirdish in neck only pup mode, but not quite as assertive or as full, could probably be a whole lot better if the pups weren't so anodyne
- Kramer XKB 10: Maple body, alu neck with maple inlays, bolt on, medium scale, after market fitted with active EMG pups, sounds mean and lean, not much wood tone though, E string has different sonic characteristic to the other strings no matter what set of strings you use, probably due to the medium scale
- Ibanez Rocket Roll: Maho body and neck, bolt on, long scale, mock mud- and minibucker in EB-3 type positions, sounds a bit like a very tame seventies EB-0L, would probably do better with original Gibson mud- and minibucker or even even the pups from an SG RI
- Gibson "V": alder body, maple neck, short scale, Ripper pups, this bass is really hopeless, the type of instrument you string with fresh strings and while you are tuning it up unplugged you already notice the sound isn't what it should be, there is not enough presence bite, the mids are too hollow, and the low frequencies are all over, but neither punchy nor of mudbucker brutishness, more like a cheap Ric copy in neck pup only mode
If this hasn't discouraged you I can still send you a tracing of the Gibson body!!!
Uwe